Automatic control for refrigerators



Oct. 20, 1931. s. G. HOUSE ET AL AUTOMATIC CONTROL FOR REFRIGRATORSyFiled April 26. 1930 5 Sheets-Sheet l Oct. 20, 1931. s. G. HousE ET AL.

AUTOMATIC CONTROL FOR REFRIGERATORS 3 sheets-sheet 2 Filed April 26.195o ATTOR N EY Oct. 20, 1931. s. G. HOUSE ET AL AUTOMATIC CONTROL FORREFRIGERATORS Filed April 26. 1930 3 Sheets-Sheet 3 WITNESS @@W PatentedOct. 20, 1931 UNITED STATES PATENT -OFFICE SAMUEL G. HOUSE REX C.SNELLM1'.AMI, FLORIDA, ASSIGNORS, BY MESN'E AS- SIGNMENTS, TO AMERICANREFRIGERATOR CAR COMPANY, OF MIAMI, FLORIDA, A

CORPORATION or FLORIDA' AUTOMATIC CONTROL FOR .'RIEIIEIRIGFIIQATOBApplication led April 26, 1930. Serial No. 447,435.

This invention relates to an automatic control for refrigerators and ismore particularlyadapted for use in refrigerator cars.

An object of the invention is the provision 5 of a device forcontrolling the flow of a refrigerating medium in a cooling unit of arefrigerating compartment through the expansion and contraction of therefrigerating medium, vthe control being effected at the in- 10 takeside of the compressor in such a manner that the temperature maintainedby the refrigerating mediuml being adapted to control a device whichlimits the flow of the refrigerating medium to the intake side of thecompressor while permitting at all times a restricted flow to theintake.

Another object of the invention is the provision of a device forrestricting the flow of the refrigerating medium to the com pressor of arefrigerating unit to prevent overload on the compressor; to relieve allrestriction when the suction pressure becomes normal; to again restrictsuction pressure when the desired temperature is obtained to preventfurther refrigeration; and t permit the refrigeration to maintain aneven temperature.

A further object of the invention is the provision of a dual control fora refrigerating unit which not only restricts the flow to the compressorto prevent overload on the compressor and to relieve all restrictionwhen the suction pressure has become normal but to control the suctionwhen the condenser coils are overheated or when the medium employed inthe first control escapes and when the first control is rendereduseless.

This invention will be best understood from a consideration of thefollowing detailed description, in view of the accompanying drawingsforming part of the specifica` tion, nevertheless, it is to beunderstood that the invention is not confined to the disclosure, beingsusceptible of such changes and lmodifications which shall define nomaterial departure from the salient features of the invention asexpressed in the appended claims.

In the drawings:

Figure l is a longitudinal vertical section of therefrigerator coilshowing our invention applied thereto,

Figure 2 is a fragmentary plan view showlng connections between the axleof the refrigerating car and the compressor and connections between themotor for temporarily driving the compressor.

Figure 3 is a vertical section of a dual control for the refrigeratingunit, Y

Figure 4 is a horizontal section take along the line 4 4 of Figure 3,

Figure 5 is a plan view of the condensing cois attached to the bottom ofthe freight car, an

Figure 6 is a vertical section of an automatic control between thecondensing and expansion units of the refrigerator system.

Referring more particularly to the drawings, 10 designates a freight carhaving axles 11 and 12 secured to the usual iianged car wheels 13 whichvellen drawn along the tracks (.not shown) caus rotation of the axlesand l1kewise a pulley 14 secured to the axle 11. This pulley drives asecond pulley 15 through a belt connection 16.

For the purpose of description, however, the pulley 15 is secured to ashaft 18 which in turn drives a pulley 19 whereby a belt 20 will drivethe pulley 21 and likewise a shaft 22 which projects beyondthe'"Hoi'lsingofy the transmission unit.

A shaft 23 is universally connected at 24 with a shaft 22 and isconnected to a shaft 25 by a universal joint 26. A clutch 27 normallyconnects the shaft with a shaft 28 which drives the rotor or pistons ofa compressor unit 29 having a header 30.

A shaft 28 may also be driven by means of a pulley 31, the pulley beingdriven by a belt 32 and a pulley 33 having direct connection with theshaft of an electric motor 34. This motor is provided with the usualwires 35 and an element 36 adapted to be connected with a source ofcurrent. A lever 37 is adapted to operate the clutch 27 whichdisconnects the shaft 25 from the shaft 28 to permit the motor 34 todrive the shaft 28 independently of its drivefrom the axle 11.

An outlet ipe 40 is connected with the header 30 of t e compressor 29and also with the condenser coils 41 secured to the bottom of thefreight car 10. These coils are disposed in a horizontal plane and areprovided with removably mounted fins 42 which aid in coiling the coilsas the air rushes through them when the car is moving. The extent ofcooling depends upon the speed of the car and the temperature of the airin the regions through which the refrigerating car is passing. Clips 43are adapted to connect the fins 42 to the sections of the coil 41.

A pipe 45 which is of restricted'diameter as compared to the coils 41connects the extreme end of said coils with an expansion valve 46, moreparticularly illustrated in Figure 6. This expansion valve includes acasing 47 with which the pipe 45 is connected. A hollow boss 48 receivesthe threaded end of the pipe 45 and -is provided with a valve 50 n whichhas a stem 51 slidably mounted in a bearing 52 at a point on the housing47 which is diametrically opposite the boss 48. A

spring 53 having one end in'engagement with a washer 54 secured'to thestem 51 and the 25 other end in engagement with a'portion of the wall ofthe housing 47 tends to maintain the valve in engagement -with its seat49. `A yoke 55 in the form of a bell crank lever` and having an arm 56pivotally mounted at 57 in the housing 47 straddles the stem 51 and isadapted to gage the washer 54 when the bell crank is oseclillated forvmoving the valve 50 away from its seat49l'as will be presentlyexplained. A pressure responsive device is shown at 60 in the form of -ahollow bellows having a rigid base member 61. A lug 62 is secured tosaid base member and is pivotally connected with the arm 56. The upperend of the` bellows is secured, at 63, to the inner wall of the housing47. This portion of the housing is provided with a hollow boss 64 whichis in open communication with 'the chamber within the pressureresponsive dvice`60. A spring 65 has one end secured to the bottom wall61 of the member 60 and the other end to a rod 66.

A cup-shaped member 67 has a hollow boss 68 threaded into the hollowboss 64. The boss 68 provides communication between the member 60 andthe cup-shaped member 67. The cup-shaped member has an annularflange 69formed integrally with the walls of the cupshaped member and this flangehas a central passage 7 0 through which is reciprocated the rod 66.

A casing 71 is threaded at 72 onto the outer wall ofthe cup-shapedmember 67 and is provided with a plate 7 3 formed integrall with thecasing at the upper end thereof.` pi e 74 has its free end connectedwith the plate 3 so that `a pressure responsive device in the form of abellows 75 will be in open communication with the pipe. The lower end ofthe bellows has a rigid portion 76 which is sep C5 .'cured to thereciprocating rod 66 The housing 47 is in communication with a dischargepipe 80 connected to the end of an expansion coil 81 which is locatedwithin a refri erating chamber 82 at one end of the freig t car 10. Apipe 83 extends from the bottom of (the coil 81 along the floor of thecar and, beneath a compartment 84 for the reception of comestibles andis connected to an expansion coil 85 located in a second re frigeratingchamber 86 at the opposite end of the car. The coil 85 has a straightreturn portion 87 extending downwardly through the refrigerating chamber86 outwardly through the bottom 87 of the car, as shown at 88, and isconnected with a control box-89 in a manner which will be presentlyexplained.

The pipe 74 extends along the top of the car and is connected with apressure bulb 90 which is located approximately midway of the chamber 86and in close association with the return pipe 87. The bulb 90 is filledwith a predetermined quantity of methyl chloride so that when thetemperature in the chamber 86 rises sufficiently the vapors from themethyl chloride will pass through the pipe 74 and enter the pressureresponsive device 75 for a purpose which will bepresently explained.

A bulb 91 is located within the chamber 84 andV has a pipe 92 extendingdownwardly through the chamber 86 and beneath the floor 'of the car andis connected with the control box 89, as shown at 93.

The control box includes a pair of parallel chambers 95 and 96 whichhave their opposite ends open. The chamber- 95 is closed by means of aplate 97 which clamps the edge of the bellows or pressure responsivewith a longitudinal passage 103 forming a guide for a valve stem 104which is secured at 105 to the bott'om of the bellows 98. The stem isslidably mounted within a passage in the top 106 of the box 99. Saidfto1s in the form of a disc threaded into said ox.

A valve 107 is secured to the stem 104 and is located within the box 99and is adapted to be moved towards or away from the top 106 of the box.The top is rovidedwith a pluralit of passages 108 an a bleeder port 109is a so included in the top. A spring 110 is in engagement with a washer11,1 resting upon the top of the plug 102.' VThe other end of the springengages the`underface of the valve 107 tending to move said valvetowards the top 106 in order to close ythe passages 108. passage 112connects a chamber 113 which is located between the bottom 114 of thebellows 98 and the top 106 of the cylindrical box 99.

Mounted within the chamber 96 is a bellows which is connected to the topofthe box 99 by means of a plate 121 and a plug 122 provides means forsecuring the open end of a pipe 123. to the top of the box whereby thepipe is placed in communication with the bellows 120. As shown moreparticularly in Figure 1, the pipe 123 is in direct communication withthe condensing coil 41 so that the bellows 120 will receive therefrigerating medium and will have the same pressure therein as do thecoils 41. The bottom of the bellows 120 is provided with a `rigid member124 which forms with the top 125 of a cylindrical box 126, a chamber127. This chamber is in communication with a pipe 128 which forms theintake for the compressor 29.

A valve stem 129 is connected to the bottom `124 of the bellows 120 andis slidable in a passage in the top 125 of the box 126 and has its lowerend guided by a hollow plug 130 threaded into a boss 131 formed on thebottom or base plate 132 of the box 126. This box is threaded at 133 tothe lower end of the chamber 96.

A valve 135 is secured to the stem 129 and is located within the chamber127 and is adapted to be moved into engagement with the top 125 of thebox 126 for closing the ports 136 formed in said top. A bleeder passage137 normally maintains the chamber 127 in communication with the box126. A spring 138 rests upon a washer 139 supported by the inner end ofthe plug 130. The other end of the spring engages a disc 140 which issecured to the stem 129.

End walls 15() are secured in any approved manner within the car 10 andspaced from the outer end walls of the car to provide the ireciprocatingchambers 82 and 86. A perforated bottom 151 is supported in the lowerend of the car and spaced from the bottom in order to permit circulationof the cooled air in the car so that when the comestibles are supportedon the member 151 the air will not only circulate through theperforations in the member 151 and through the comestibles but alsobeneath the member 151 and over the top edge of the end walls which arespaced from the top of the freight car.

The operation of my device is as follows: The cooling or refrigeratingmedium is supplied to the system in any approved manner and as long` asthe car is remaining idle the compressor 129 will not be forcing thererigerating medium. such as methyl chloride, under pressure into thecondensing coils 41 and the temperature in the space 84 in the on. therefrigerating medium 1n t e condenser co1ls 14.

Due to the fact that the temperature in the n chamber 86 at starting isrelatively high, the medium, such as methyl chloride, in the pressurebulb 90 will be expanded and act on the expansionchamber; 75, therebycausing the rod 66 to be moved yinwardly until it rests on member 69.The spring 65 will be compressed against the tension of spring 53permitting valve 50 to o en sothat a quantity of the condensed re rierating medlum will enterchamber 47 am? ex and until the ressure of theexpanded me 'um overcomes t e pressure in the bellows 60 when the valve50 will be closed by the spring 53. As soon as the suction in pipe 80has increased suiiciently to reduce the pressure in chamber`47, thepressure in the chamber 60 will cause member 61 to move inwardly androck the yoke 55 and o en valve 50. The expansion of the methyl c loridein these coils and in the pipe 83 will eventually reduce the temperature1n both chambers 81 and 86 until the proper refrigerating temperature ishad.

At the inltial operation of the pump 29 the temperature, as has beenexplained, in 95 the chamber 84 is at its maximum and the methylchloride in the pressure bulb 91 will expand, causing the gas to exert apressure within the expansible chamber 98 through the tube 92 and tendto retain thcvalve 107 0.

away from the ports 108 so that the suction end of the intake side ofthe compressor will be receiving the evaporated refrigerating medium fora continuance of the cycle of said medium through the system.

However, the pressure in the pipe 88 and chamber 113 will be the same asin the bellows 98. Since the compressor is operating, and because thepressure on both sides of the bottom`114 of the bellows is equalized theu.

spring 110 will close the valve 107. When the compressor is set inoperation the pressure in the chamber 113 will be reduced sufticientlyto permit the bellows 98 to open the valve 107 and the medium will bedrawn on 11| its return to the compressor as long as the pressure in thebellows 98 is suiiicient to overcome the action of the spring.

When the 'temperature in the chambers 82 and 86 has been suiiicientlylowered or the 1g.

temperature reaches a degree which is desired, the medium in thepressure bulb 91 will be condensed as will be the medium in the pressurebulb 90. Thus the expansible chamber 75 will be contracted and throughthe various 125 elements permit the valve 50 to be moved towards closedposition, thereby reducing the quantity of the refrigerating mediumpassing from the condensing coils 41 to the expansion coils 81 and 85.The lowering the temperal ture in the chambers 84 and 86 will causocontraction of the medium in the pressure bulb 91 so thatl the spring110, shown more particularly in Figure 3, Will be permitted to move thevalve 107 in close association with the closure plate 106 of thecylindrical member 99 and restrict the low of the refrigerating mediumfrom the pipe 88 to the intake side of the compressor 29. If thetempera-- ture should be sufficiently lowered to cause the expansiblemember 98 to permit the valve 107 to be closed, a predetermined quantityof the refrigerating medium will pass from the pipe 88 into thecylindrical box 99, through the bleeder port 109, through the conduit112 and through the cylindrical member 126, ports 136 and the pipe 128to the intake side of the compressor.

The spring 110, the bleeder port 109 and the control by the pressurebulbs 90 and 91 are so regulated that predetermined pressures will bemaintained in the refrigerating system at all times during the travel ofthe freight car. This travel Will permit, due to such regulation aspreviously explained, considerable variance in the speed of the freightcar. v

If at any time it is necessary to sidetrack the car, for any purpose,the member 36, as shown 1n Figure 2, may be connected with a source ofcurrent for causing rotaton of the motor 34 and a pulley 31 after theclutch member 27 has been thrown out to disconnect the shaft 28 from theshaft 23. By this means the temperature of the car can be maintaineduniform regardless of the length of time`it is sidetracked providedhowever that. the current is available.

When the freight car is travelling normally along the roadbed the belt32 is disconnected from the pulleys 31 and 33 to prevent unnecessaryoperation of the motor 34.

The valve 135 comes into play when a dangerousl high temperature ismaintained in the coo ing coils 41 for some reason. Certain of thesereasons include the travel of the freight car through a region where theground is extremely warm so that the cooling effect ofthe fins 42 on thecoils is insullicient. At this time the high pressure in the coils 41 istransmitted through the pipe 123 to the expansible member 120 so that itwill move 1n a direction to cause the valve 135 to be seated upon themember 125 which is threaded into the top of the cylindrical box 126.The port 137, however, ermits a predetermined quantity of the reigerating medium to pass to the pipe 29 and tothe intake side of thecompressor. The closing of the valve 125 will prevent the greaterportion of the refrigerating medium from being drawn into the compressorand thereby relieve the compressor of its load.

We claim:

1. In a refrigerating unit, a compressor,

condensing coils connected with the compressor, expansion coils havingrestricted communication with the condensing coils, a return pipeconnecting the expansion coils With the intake of the compressor, apressure control unit interpolated in the return pipe and including avalve, means associated with the expansion coils for actuating the valvefor restricting the return of a refrigerating medium from the expansioncoils to the compressor in accordance with a drop in temperature of themedium surrounding the expansion coils.

2. In a refrigerating unit, a compressor, condensing coils connectedwith the compressor, an expansion coil having a restricted communicationwiththe condensing coils. a. second expansion coil directly connectedwith the first expansion coil, a return pipe connecting the secondexpansion coil with the compressor, a pressure control unit interpolatedin the return pipe and including a valve, means associated with theexpanson coils for actuating the valve for restricting the return of arefrigerating medium from the expansion coils to the compressor inaccordance with a drop in temperature of the medium surrounding thesecond mentioned expansion coil.

3. In a refrigerating unit, a refrigerating chamber, compressor,condensing coils located exteriorly of the chamber and connected vWiththe compressor, expansion coils in communication with the condensingcoils, a return pipe connecting the expansion coils with the intake sideof the compressor, a pressure control unit interpolated in the returnpipe and including a pair of valves, means associated with one of theexpansion coils for actuating one of the valves in accordance with adrop in temperature of said expansion coil for restricting the ilow ofthe refrigerating medium from the expansion coils to the intake side ofthe compressor, means responsive .to excessive pressure in thecondescending coils for restricting communication between the expansioncoils and the intake side of the compressor.

4. In a refrigerating unit, a compressor, condensing coils connectedwith the compressor, expansion coils having restricted communicationwith the condensing coils, a return pipe connecting the expansion coilswith the intake of the compressor, a pressure control unit interpolatedin the return pipe and including a valve, means associated with theexpansion coils for actuating the valve for restricting the return of arefrigerating medium from the expansion coils to the compressor inaccordance with a drop in temperature of the mediumsurrounding theexpansion coils, the pressure control unit being provided with a bleederport permitting a restricted flow of the refrigerating medium around thevalve when said valve is closed.

5. In a refrigerating unit, a refrigerating chamber, a compressor,condensing coils located exteriorly of the chamber and connected withthe compressor, expansion coils in communication with the condensingcoils, a return pipe connecting the expansion coils with the intake sideof the compressor, a pressure control unit-interpolated'in the returnpipe and including-a pair of valves, means associated with one of theexpansion coils for actuating one of the valve in accordance with a dropin temperature of said expansion coil for restricting the flow of therefrigerating medium( from the expansion coils to `the intake side ofthe compressor, means responsive to excessive pressure in the condensingcoils for restricting communication between the expansion coils and theintake side of the compressor, said pressure control unit being providedwith a bleeder port associated With each valve to permit a restrictediiow of the refrigerating medium from the expansion coils to the intakeside of the compressor.

6. In a refrigerating unit, a refrigerating chamber, a compressor, coilslocated exteriorly of the chamber and connected with the compressor,expansion coils in communication with the condensing coils, a returnpipe connecting the expansion coils with the intake side of thecompressor, a pressure control unit interpolated in the return pipe andincluding a pair of valvesfmeans associated with one of the expansioncoils for actuating one of the valves in accordance With a drop intemperature of said expansion coil for restricting the flow of therefrigerating medium from the expansion coils to the intake side of thecompressor, means responsive to excessive pressure in the condensingcoils for restricting communication between the expansion coils and theintake side of the compressor, said pressure control unit being providedWth bleeder ports for maintaining a restricted flow of the refrigeratingmedium to the intake side of the compressor from one of the expansioncoils when either or both of the valves are closed.

7. In a refrigerating unit, a compressor, a condenser connected with thecompressor, al1 expansion chamber having controlled communication withthe condenser, a pressure control unit connected with the expansionchamber, a pipe connecting the unit with the intake side of thecompressor, said unit including a valve for controlling the iovv of arefrigerating medium from the expansion chamber, a temperatureresponsive device having means subject to pressure of the intake slde ofthe compressor for controlling the valve.

8. In a refrigerating unit, a compressor, a condenser connected with thecompressor, an expansion chamber having controlled conimunication withthe condenser, a pressure control unit connected with the expansionchamber, a pipe connecting the unit with the intake side of thecompressor, said unit including a valve for -controlling the low of arefrigerating medium from the expansion chamber, a temperatureresponsive device having means subject to pressure of the intakel sideof the compressor for controlling the valve, said unit including ableeder port for maintaining the expansion chamber in restrictedcommunication with the intake side of the compressor.

9. In a refrigerating system, a compressor, means for controlling theintake side of the compressor and comprising a chamber, a partitiondividing the chamber into a pair of sections and provided with ports forplacing the sections in communication with each other, a valve forclosing said ports, an expansible member carrying a valve stem to whichthe valve is secured, one of the sections being in open communicationwith the expansion chamber of the system, the other section being incommunication with the intake sides of the compressor, a temperatureresponsive means in a refrigeratng compartment of the system subjectingthe expansible member to pressure for opening the valve, and a. springtending to close the valve, the expansible member being subject topressure from the intake side of the compressor, such .pressureco-operating with the spring and pressure Within the expansible memberto control the valve.

l0. In a refrigerating system, a compressor, means for controlling theintake side of the compressor and comprising a chamber, a partitiondividing the chamber into a pair of sections and provided with ports forplacing the sections in communication with each other, a Valve forclosing said ports, an expansible member carrying a\ valve stem to whichthe valve is secured, one of the sections being in open communicationwith the expansion chamber of the system, the other section being incommunication with the intake sides of the compressor, a temperatureresponsive means in a refrigerating compartment of the system subjectingexpansible member to pressure for opening the valve, and a springtending to close the valve, the expansible member being subj ect topressure from the intake side of the compressor, such pressureco-operating with the spring and pressure'within the expansible memberto control the valve, ,said partition having a bleeder port for-retarding the closing or opening of the valve While maintaining theexpansion chamber of the system in restricted communication with theintake side of the compressor.

11. In a refrigerating system, a compressor, means for controlling theintake side of the compressor and comprising a chamber, a partitiondividing the chamber into a pair ino izo

6 Y Lezama of sections and provided with ports for placin the sectionsin communication with each ot er, a valve for closing said ports, anexpansible member carrying a valve stem to 5 which the valve is secured,one of the sections being in open communication with the expansiblemember of the system, the other section being in communication with theintake sides of the compressor, a temperature l responsive means in arefrigerating compartment of the system subjecting the expansible memberto pressure for opening the valve, and a spring tending to close thevalve, the expansible member being subject to pressure l from the intakeside of the compressor, such pressure (2o-operating with the spring andpressure within the expansible member to control the valve, and means'for varying the pressure on the s rin 0 SALiMUL G. HOUSE.

REX SN ELL.

